The 63-year-old ran a slick and persuasive campaign selling himself to the country's aspirational voters as someone who can revive India's flagging economy, stamp out corruption, and place the nation on the pedestal that the world's largest democracy should be on.

His achievements as an economic manager as chief minister of Gujarat need to be recognised.

The state ranks in the top five when it comes to most indicators such as economic growth and agricultural production. It is also regarded as a place where people can do business.

Many others see a much darker side though. The easiest thing to point to are the deadly riots in Gujarat in 2002, when clashes between Hindus and Muslims left more than 1,000 people dead. Most of those killed were Muslims.

Mr Modi was the chief minister at the time and he is accused of standing back and letting the violence unfold.

He has never been charged over the riots, but some of his supporters have been convicted for their complicity – and are now sitting in jail. It is an easy connection to make.

Mr Modi's fiercest critics envision him inflaming the sectarian divide in Indian society and unleashing havoc on minority groups across the country.

But this extreme scenario is not likely to eventuate. Mr Modi's campaign largely underplayed his Hindu nationalist credentials, instead focusing on his record as an economic reformer.

Fears non-Hindu minorities will be silenced under PM Modi

Most commentators agree that the man who started off his political career under a cloud of sectarian violence will be too smart to begin his reign as prime minister in the same way.

Instead, what they fear is the gradual marginalisation of India's minority groups.

Mr Modi's party, the BJP, has very few non-Hindu candidates.

His tacit warning to minorities such as Muslims and Christians is don't politically co-ordinate work against me and you will be fine.

Commentator Hartosh Singh Bal

India's other major party, Congress, has traditionally been the party most Indian Muslims vote for.

It has some high-profile Muslim politicians, including external affairs minister Salman Kurshid.

In contrast, the numbers of Muslims and Christians within the ranks of the BJP are low.

New Delhi-based commentator Hartosh Singh Bal contends the voices of minority groups will be quieter in an India run by Mr Modi.

"Just by his presence there is a messaging that says, you know your place, do your day-to-day work," he says.

"His tacit warning to minorities such as Muslims and Christians is, 'Don't politically co-ordinate [or] work against me and you will be fine'.

"And I think the danger we're running into is a majoritarian rule where the minorities are told, 'You know your place, you will be fine'. That's not the type of country this has been until this point in time."

Modi's mixed results in Gujarat state

The big fear is not of state-sanctioned violence. It is of militant groups becoming emboldened by Mr Modi and taking matters into their own hands.

It is a frightening scenario, and there are constant reminders of the tinderbox that lies beneath the surface of Indian society.

During the campaign deadly violence broke out in Assam between Hindus and Muslims. Likewise, just this week, riots between Sikhs and Muslims in Hyderabad killed several people.

Last year dozens of Muslims were killed in riots in Muzzafarnagar, a town in Uttar Pradesh, only a few hours outside of New Delhi. It was some of the worst ethnic violence in decades – and there are allegations that local BJP politicians stirred it up.

And while Gujarat's economic growth has outstripped most of India during Mr Modi's tenure, not all indicators paint a positive picture of life under so-called Modinomics.

Last year, UNICEF stated that social development indicators have not kept pace with economic development in the state that has a population of 60 million.

It pointed out the rates of infant and maternal mortality rates had shown scarce signs of improvement during Mr Modi's tenure, and that almost every second child in Gujarat under the age of five years is undernourished and 75 per cent are anaemic.

But there were a lot of ticks for Mr Modi's efforts to improve Gujarat.

UNICEF acknowledged progress in guaranteeing water supplies to rural areas, and said there were also significant improvements made in providing primary school educations to the poor sections of Gujarati society.

In all, a mixed bag. But they are statistics that would be mirrored across most states in India. In many cases, the situation is far worse than in Gujarat.

Economists back change of power in Delhi

There are many people with concerns about Mr Modi – but there are just as many who baulk at considering the alternative situation. What course would a tired and clapped-out Congress administration take India on?

Whether they back Mr Modi or not, most Indians think it is time for a change from Congress.

Congress's putative prime ministerial candidate, Rahul Gandhi, has not captured the hearts or the imagination of Indian voters. Congress, India's founding political party, is now associated with ineptitude and at times downright corruption.

Indeed, Mr Modi played this up during the campaign.

The son of a modest tea store owner has also been quick to point out his opponent's high-born connections. His efforts to portray Rahul Gandhi - a descendent of India's first prime minister - as the indifferent scion of a dynasty that has had its day in Indian politics appear to have worked.

On the day before counting day, India's leading stock index the Sensex rose to record heights.

Economists are also predicting higher levels of growth once the uncertainty of the election period is over.

More than 500 million people have voted in this election, an event described as the world's largest exercise in democracy. They have sent Mr Modi into power with a workable majority, but it will certainly not be business as usual here in India.